Compressive stripping unit and indexing type nibbling punch for turret punch presses and the like



J. S. KILLALY Jan. 10, 1967 COMPRESSIVE STRIPPING UNIT AND INDEXING TYPENIBBLING PUNCH FOR TURRET PUNCH PRESSES AND THE LIKE Filed Jan. 8, 19655 Sheets-Sheet 1 INVENTOR. Jail]? 5. fii'lla 1], BY

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m m y 11%? J. s. KILLALY fififi COMPRESSIVE STRIPPING UNIT AND INDEXINGTYPE NIBBLING PUNCH FOR TURRET PUNCH PRESSES AND THE LIKE Filed Jan. 8,1965 a Sheets-Sheet 2 3 Mm M5 7429 $5 $5) if INVENTOR.

Jam. W, WW I. s. KlLtALY 3,2963% COMPRESSIVE STRIPPING UNIT AND INDEXINGTYPE NIBBLING PUNCH FOR TURRET PUNCH PRESSES AND THE LIKE Filed Jan. 8,1965 C5 Sheets-Sheet 3 I N VEN TOR.

United States Patent This invention relates to certain improvementsadapted for turret punch presses or for single station presses usedmainly for low production work. In this type of press activity, theblank is placed in a pantograph or a duplicator type press or anumerically controlled type press, whether it be a turret punch press ora single station punch press. Each stroke of the punch or ram producesonly one hole, notch or nibble in the blank. The blank is clamped inwork holders or is manipulated manually underneath the punch stationuntil the entire hole pattern is punched.

The above-described type of press activity differs basically from thatinherent with presses set up for high production work wherein multiplepunches are mounted in the press and a single stroke produces a numberof holes and cut-outs or completely finishes the work.

The design and construction of the low production type of punch pressdiffers in many important respects from that of the high productionmachines. Considering the stripper or apparatus which presses the blankoff the punch on the withdrawal stroke, in the low production pressesthe stripper must be confined within a certain limited diameter punchholder. Movement of the stripper must be limited within a certainvertical distance and, most important, the top half of the press mustnot be connected to the bottom half in any way which restricts movementof the work piece in the press.

The prior art teaches a positive stripper adapted for the low productiontype of press mounted usually on the lower face of the upper turret and,on a single station press, mounted on the press frame. The disadvantagesof these types of construction are that the blank is not positively heldagainst the working surface or die and tends to hang up on the punchduring withdrawal and becomes distorted while traveling the distancerequired to contact the bottom of the positive stripper. The blanksometimes sticks to the punch and slides off to one side thereby causingdouble slugging when the ram trips again. These movements of the blankare injurious to the punch and die as well as the blank. Also, the priorart type of positive stripper actually forms the blank when there areseveral holes to be punched lose together in light gauge materialrequiring the removal and straightening of the piece before theremaining holes can be punched. Further, the constant banking of theblank up against the positive stripper creates a peening action whichcauses inaccuracies in locating subsequent holes and results inrejections of close tolerance parts.

Thus, it is the primary advantage of the compressive stripping unit ofthis invention that the blank material is held stationary on the diesurface during punching and stripping movement of the punch. Therefore,it is not possible for the slug to stick to the punch and doubleslugging as well as damage to the tools and blanks is avoided. Thecompressive stripper holds the blank perfectly flat, insures accuracesunavailable to the positive stripper even on light gauge material.

In addition to the compressive stripping unit adapted for the turretpunch type of press, this invention teaches a novel constructionnibbling punch which is adapted for and within the price range of thoseengaging in the low production type of punch press activity. Similar tothe compressive stripper, the nibbling punch of this invention 3,2%,%5Patented Jan. 110, 11967 "ice is confined within a certain diameterpunch holder and within certain up and down dimensions. This nibblingpunch can be indexed as desired around its vertical axis to produceangular notches and nibbles as well as angular sheer cuts. The nibblingpunch can punch out round, square, rectangular, oval, and odd-shapedopenings which far exceed the tonnage capacity and other physicalcapabilities of the press being used.

It is the further advantage of the improvements of this invention thatthey are relatively simple in design, in expensive to manufacture anduse, and readily and easily substitutable in the well-known turret orsingle station type of press. These features are particularly important,as indicated above, when, in those instances, the press is designed foruse in low production type of work.

These and other advantages of this invention will become more apparentfrom the description set forth hereinbelow and from the drawings,wherein:

FIG. 1 is a view partly in side elevation and partly in section, with acut-away portion, of the preferred form of the compressive strippingunit of this invention;

FIG. 2 is a partial view similar to that of FIG. 1 showing the press inthe upward or withdrawal stroke;

FIG. 3 is an exploded perspective view of the stripping unit shownotherwise in FIGS. 1 and 2.

FIG. 3a is a perspective view partly cut away of an alternate type ofstripper;

FIGS. 4 and 5 are perspective view of strippers for use with a punchhaving a different shaped cutting surface;

FIGS. 6 and 7 are sectional views of alternate types of strippers;

FIG. 8 is a view partly in side elevation and partly in section, with acut-away portion, of the preferred form of indexing type nibbling punchequipped with a compressive stripper;

FIG. 9 is a partial view of the punch shown in FIG. 8 during thewithdrawal movement of the punch;

FIG. 10 is a sectional view of the punch support taken along the linesand arrows X-X of FIG. 8;

FIG. 11 is a sectional view taken along the lines and arrows XIXI of thestripper and punch as shown in FIG. 9;

FIG. 12 is an exploded perspective view of the indexing type nibblingpunch shown in FIG. 8;

FIG. 13 is a reversed exploded perspective view of the shank and punchhalf members forming part of punch as shown in FIG. 12; and

FIG. 14 is a partial perspective view of the nibbling punch, blank anddie.

The following description is directed to the specific forms of theinvention illustrated in the drawings and is not intended to limit thescope of the invention itself which may be practiced in a variety offorms and arrangements.

In the drawings and written description set forth herein, only generalreference is made to the well-known features of the standard turret orsingle station type press and the like and this disclosure is largelydirected to the novel structure in the form of improvements which aredesigned for incorporation in said standard type presses. Referring toFIG. 1 of the drawings, the punch and compressive stripping unit of thisinvention are designated generally by the numeral 15 and said componentsare supported at the top by a press member 16 which also includes aworking surface 17 along the top of the female die 18. Components 15move in a vertical direction under control of the operator in relationto the stationary and horizontal die 18. The unit 15 includes,basically, three components: a punch support 20, a pnuch 30 and a sleeve40.

Referring now to FIG. 3, the components of the stripping unit are shownin exploded perspective view. A generally cylindrical punch support hasa main body portion 21 of a first diameter and a second body portion 22located the-rebeneath of a lesser diameter thereby defining an annular,downwardly-directed shoulder 23. A top supporting T-shaped flange 25fits within a correspondingly shaped groove 16a in the press member 16.Punch support second body portion 22 is recessed at 24 and a cylindricalhole is formed in support 24) so as to accept a punch which has a topcylindrical portion 32 (shown in dotted lines) and a generally cubicalpunch block portion 33 with an inwardly tapered cutting surface 35. Thepunch 30 is held within support 29 by a bolt 36 shown in dotted lines.Punch support second body portion 22 has a threaded hole 37 toaccommodate a stud or pin 38 for reasons described below. It should beunderstood that, during operations, the support 20 and punch 30 move asa single unit, on the downward stroke to punch a hole in a blank mountedon the die and then upwardly and clearing so that the blank can berepositioned.

A compression spring 39 is provided of such diameter to fit around thepunch support second body portion 22 and is of less diameter than thatof the support main body portion 21.

A generally cylindrical stripper sleeve 40 having a top inwardlydirected flange 42 of a minor diameter slightly larger than that ofportion 22 and an outside diameter similar to that of portion 21 islocated on portion 21 for partial independent movements in relationthereto. An axial directed slot 44 is provided in the wall of sleeve 40.Sleeve 40 has a downwardly directed bottom annular surface 46 which islocated approximately level with the cutting surface of the punch whenthe punch and sleeve are lifted clear of a blank. Sleeve flange 42 formsan upwardly-directed annular surface 45.

A flat, round disk 50 serves as a stripper or stripper plate in thisembodiment and said stripper has an outside diameter similar to that ofthe sleeve 40. Stripper 50 may originally be provided with an opening 52which corresponds very closely to the outside diameter of the punch 30or said disk may be solid when installed and thereafter punched out onthe first stroke of the punch.

The components are assembled as shown in FIGS. 1 and 2 wherein thespring is placed on portion 21 followed by sleeve and stud 38 is placedwithin slot 44 and threaded in hole 37. Spring 39 then acts againstshoulder 23 and surface to urge the sleeve downwardly until stud 38engages the top limit of slot 44. This is substantially the positionshown in FIG. 2. The metal stripper plate is attached to the bottomsurface 46 of sleeve 44, in this instance, by a plurality of smallmagnets which are mounted in the surface 46 and these are suflicient tohold the stripper in position during operation of the press.

Operation of this preferred form of compressive stripping unit issubstantially as follows:

The punch support 20 and punch 30, together with sleeve 40 and stripper50, are raised sufficiently clear of the working surface 17 of the die18 to allow a blank or slug material B to be placed on surface 17 andpositioned as desired beneath the punch. As the press begins itsdownward movement, the stripper 50 contacts and presses downwardly onthe blank B slightly before or at the same time as the punch cuttingsurface 35 contacts the blank. The blank is thereby held stationary ondie surface during the entire downward movement as the punch passesthrough the blank knocking out piece B. As shown in FIG. 1, spring 40 isthereby compressed and it is evident 'that the pressure exerted by thestripper and sleeve on the blank may be varied by substituting differentcompression strengths springs. As the press begins to move upwardly, asshown in FIG. 2, the spring continues to press the stripper againstblank B holding the blank on the die while the punch passes back throughand finally out of the blank. This continuous compressive action of thestripper prevents the blank from sticking to the punch and preventsdouble slugging upon the return downward stroke of the punch. By'holdingthe blank on the die, the compressive stripper insures accuracy of thepunching and prevents peening action in light gauge blanks.

The compressive stripping unit shown in FIG. 3 may be modified bysubstituting for stripper 50 the stripper shown in FIG. 3a which, inthis form, has a top metal disk 50a and a similarly shaped compressiblematerial 39a, such as plastic, rubber or neoprene, attached to thebottom thereof. In a stripping unit incorporating the stripper of FIG.3a, the sleeve 40 is fixedly attached to support body portion 22 andspring 39 is dispensed with as the compressible stripping material 39apresses against the blank B and flattens out to absorb the downwardmovement of sleeve 40 during the punching stroke. During withdrawal ofthe punch, the stripper material 39a presses with sulficient force tohold the blank B in position on the die 18.

Of course, it should be understood that the shape and size of the punch30 and particularly the cutting surface 35 may be varied from the squareshape shown in FIGS. 1 to 3 to a round and hexagonal shape as indicatedby the strippers shown in FIGS. 4 and 5.

Modifications of the means for attaching the stripper to the sleeve areshown in FIGS. 6 and 7. Stripper 60, shown in FIG. 6, has a flat diskportion 61 and flexible side portions 62 which may be snapped over thelower surface of sleeve 40 into an annular groove 63 formed in thesleeve. In FIG. 7, the stripper 65 formed from metal, rubber or plastichas threads formed on flanges 66 which correspond to threads 67 formedalong the bottom edge of the sleeve 40.

Indexing type nibbling punch The preferred form of indexing typenibbling punch, equipped with a compressive stripper, of this inventionas designed for a turret type punch press and the like is shownassembled in FIG. 8 and identified generally by the numeral 69. Thepunch 69 is supported at the top by the press member 16 and moves up anddown relative to the stationary, horizontal work surface 17 and femaledie 18.

Referring to the exploded perspective view of the punch 69 shown in FIG.12, a generally cylindrical punch support 70 is provided with anupwardly-extending, T-shaped flange 71 which fits within acorrespondingly shaped groove in member 16 and, at its base, support 70has a cylindrical hole 72 and a series of threaded holes 73 extendinginwardly to the hole 72. A threaded stud 74 is provided to thread in anyone of the holes 73 to engage a whistle groove 81 formed in shank of theshank half member 82 thereby preventing shank 80 from being removed fromhole 72 as described further below. The bottom or downwardly directedsurface of punch support 70 is provided with a series of radiallydirected continuous grooves 75 which are of such size as to receive anindexing pin 76 therein otherwise mounted in the shank half member 82for adjustment of shank half member 82 in a number of positions aroundits vertical axis in relation to punch suport 70, as described furtherhereinbelow.

Generally cylindrical half member 83 having an outside diameter slightlyless than that of the punch support 70 is composed of an upper shankhalf member 82 and lower punch half member 100 which are held togetherby a pair of bolts 107 (FIG.13), the member 82 having a flange 82apositioned within recess 100a of member 100. Shank member 82 is providedwith, in addition to shank 80, four uniform diameter equally spacedholes 84 extending upwardly from the bottom surface. Four nibbling heelshaving a small diameter neck 92, an axial slot 93, a flat axial surface94 and a snap ring 91 are mounted for limited axial or up and downmovement in holes 84, being spring biased downwardly by springs 86.Shank half member 82 also has at least one bore 82b in which theindexing pin 76 is located extending therefrom into punch support 70 andaligning pins 82c.

Punch half member 100 has a generally cubical punch 110 with cuttingsurface 111 fixedly attached to said member and has four holes or bores102 (FIG. 13) of the same size and location as holes 84 in shank halfmember 82, said holes 102 being continued to grooves 164 in the sidesurfaces of punch 110. The heels 911 are mounted in half member 100(FIG. 8) so that the springs $6 are concentric to heel necks 92 and thesnap rings 91 prevent the escape of the heels out of punch half member100. Each heel 90 is prevented fro-m rotating in its groove 104 in punch110 by pins 195' and springs 106 mounted in hori Zontal bores 105a, saidpins 165 being spring biased into longitudinal or axial slots 93 in theheels 9% thus allowing axial movement of the heels but not rotarymovement. The heels 9!) are mounted in punch 110 so that their flatsides 94 form part of the side surface of the punch 111) as shown inFIGS. 11 and 12. These flat sides, specifically, as well as theremaining surface of the punch are of such dimension to fit tightlywithin the opening 136 formed in the female die 18 when the punchdescends as shown in FIGS. 8 and 9.

The compressive stripper apparatus 121), modified for the nibblingpunch, comprises a conical spring 122 of a diameter slightly larger thanthe punch 11%, a cylindrical sleeve 124 with an inner diameter onlyslightly larger than the half member 100 and having an inwardly-directedshoulder 124a formed on the bottom end thereof (FIG. 9), and a flat diskstripper 128. Sleeve 124 has an axial slot 123 and a pin 125 is providedto thread Within hole 126 in punch member 100 to hold the sleeve withincertain limits within an axial or upward and down movement. As shown inFIG. 9, sleeve 124 is mounted on member 83 and spring 122 surroundspunch 110 and is mounted between the flat downwardly-directed surface103 of punch half member 100 and the annular upward facing surface 124::of the sleeve, thereby continually urging stripper 128 into contact withthe blank B when the punch begins to descend.

The operation of the preferred form of the indexing nibbling type punchpress is substantially as follows. The press is raised sufficiently highto allow a blank to be inserted therebeneath and positioned on the die18. As described above, the nibbling punch is particularly designed forpunching out a piece of material which is smaller in size than the totalarea of the punch cutting surface or face. As shown in FIG. 14, theblank 134 has a pre-punched hole 135 and is positioned on the die 18 sothat a piece 134a shown in dot and dash lines will be cut out in thefollowing stroke. As the press descends, all of the heels 90 are springbiased downwardly in advance of the bottom cutting surface of the punch.When a heel contacts the blank it is forced upwardly until it bottoms inhole 84 in member 82 and the bottom cutting surface of that heel assumesa position level with the remaining cutting surface of the punch andperfoms like any other part thereof. The important work is achieved bythose heels which do not contact the blank, for instance heel 90a inFIG. 14, as this heel then precedes the punch and passes directlythrough the hole 135 in the blank and into and against the side of thedie 18 as shown in dotted lines. Because this heel 90a is within the diebefore or at the time the remaining surface of the punch contacts theblank, the punch is prevented from moving sideways or shearing theblank. Of course, secondary movement of the blank is also prevented andan accurate, clean cut is produced.

The nibbling punch of this invention can punch out round, square,rectangular, oval and odd-shaped openings which far exceed the tonnagecapacity and other physical capabilities of the punch used. Bysubstituting a quadrant punch for the nibbling punch shown, much largerholes can be produced in material which, otherwise, would far exceed thecapacity of the press used.

By means of the indexing grooves 75 formed in the bottom of support 70,the indexing pin 76 mounted in member 82 and the removable stud 74, theshank and punch half members may be separated from support 70 androtated so as to position pin 75 in a different groove. This causes thepunch to assume a new position relative to the work blank with a minimumof time and effort.

The punch indexing apparatus as shown in FIG. 8 can be modified byproviding a series of radially directed holes in shank 80 of such sizeas to accept stud 74 therein and a vertically positioned supporting boltextending through support 71) and into shank 80 as shown in theapparatus of FIG. 1. Radially directed grooves 75 formed in the bottomof support '70 can be dispensed with along with indexing pin '76 and itscomplementary hole formed in member 32. The shank and punch half membersmay be indexed or rotated a portion of a revolution by loosening thevertical bolt and retracting stud 74 from its first hole. When the halfmembers and punch are positioned as desired, the stud is threaded into asecond aligned hole in the shank and the supporting bolt tightened.

The compressive stripper functions with the nibbling punch as with theordinary punch shown in FIGS. 1 and 2. As indicated in FIGS. 8 and 9,the stripper 128 extends beyond the punch and heels and contacts theblank slightly before or at the same time the heels come into contact.The work piece is thereby held stationary on the die while the punchcontinues to descend and then on the withdrawal stroke until the punchis clear of the blank as shown in FIG. 9.

Although this invention has been disclosed with referenoe to specificforms and embodiments thereof, it will be appreciated that a greatnumber of variations may be made without departing from the spirit orscope of this invention. For example, parts may be reversed, equivalentelements may be substituted for those specifically disclosed, andcertain features of the invention may be used independently of otherfeatures, all without departing from the spirit and scope of thisinvention as defined in the appended claims.

I claim:

1. A turret type press punch or the like having a punch mounted forvertical movement relative to a work surface, a compressive typestripping unit mounted for partial movement with the punch comprising asleeve surrounding the punch having a downwardly directed surfaceadjacent the punch cutting surface and having means for attaching asleeve to the punch so that the sleeve moves partially with the punchbut is free to move within defined limits in vertical directionsrelative to the punch,

compression spring means for continually urging the sleeve in thedirection of the work surface, said spring rneans being mountedconcentric to one portion of the press and bearing on an upwardlydirected surface of the sleeve,

a stripper comprising a flat metal disk supported by the sleeve on itsdownwardly directed surface by a plurality of magnets located within thedownwardly directed surface of the sleeve, said stripper forming asurface contiguous to and in the same plane as the punch cutting surfacewhen said surface is not in contact with the blank whereby uponpositioning of the blank and lowering of the punch proximate the blankthe stripper contacts and presses the blank against the work surfacewhile the punch passes through the blank and as it is withdrawn,

an axial directed slot formed in the sleeve and a stub mounted in thepunch and extending through said slot, whereby movement of the sleeveindependent of the punch is determined by the limits of the slot.

2. The punch press as defined in claim 1 further including a punchsupport having a main portion supported at the top by the press and asecond portion at the bottom of the main portion having a lesserdiameter, the two portions of the punch support forming therebetween adownwardly directed annular shoulder, the punch support holding thepunch partly within and partly extending from the bottom end thereof,and the annular shoulder forming the upper supporting surface for thecompression spring.

3. In a turret type punch press or the like, a nibbling punch comprisinga punch and support member mounted for vertical movement relative to astationary female die, said punch having a plurality of uniform diametergrooves extending therethrough from the cutting surface and extendinginto the support member as holes, said grooves being located contiguousthe vertical sides of the punch so that the flat side surfaces of thepunch truncate the grooves causing their perimeter to be less than 360,

a plurality of generally cylindrical heels equal in number to the numberof grooves, each of said heels having an axially directed flat surfacewhich forms part of the vertical side surface of the punch when inassembled condition, said heels mounted in the grooves and holes forvertical movement independent of the punch and punch support withincertain limits,

means for preventing the heels from rotating,

means for continually urging the heels in the direction of the die sothat the heels extend beyond the downwardly directed cutting surface ofthe punch when not forced upwardly by the blank upon downward movementof the punch, whereby following positioning of the blank on the die andlowering the punch, each heel which does not contact the blank movesinto the die before or at the same time as the punch contacts the blankthereby preventing lateral movement of the punch when only a portion ofthe punch cutting surface contacts the blank, a punch support locatedabove and supporting the punch and support member for vertical movement,said punch support having a plurality of indexing openings locatedwithin its downwardly directed bottom surface,

said support member having at least one indexing pin mounted verticallywithin and protruding from said member, said pin being of such size asto fit within one of said indexing openings in the punch support,

means for detachably connecting the punch support and supporting memberso that upon detaching said means the support member may be rotatedaround its vertical axis to a selected position until said pin fitswithin a selected hole whereby the position of the punch around itsvertical axis may be varied.

4. The nibbling punch defined in claim 3 further including a strippersleeve mounted for independent axial movement on the supporting memberhaving a downwardly directed surface located adjacent the punch cuttingsurface when not contacting the blank and having means for attaching thesleeve to the punch so that the sleeve moves partially with the punchbut is free to move independently within defined limits in a verticaldirection relative to the punch,

means for continually urging the sleeve in the direction of the die, and

a stripper supported by the sleeve on its downwardlydirected surface andforming a surface contiguous to and in the same plane as thedownwardly-directed surface of the punch heels when not contacting theblank whereby following positioning of the blank and lowering of thepunch proximate the blank, the stripper contacts and presses the blankagainst the die during the time the punch passes through the blank andis withdrawn.

5. The nibbling punch as defined in claim 4 wherein the means forcontinually urging the sleeve in the direction of the Work surfacecomprises a compressing spring surrounding the punch and located betweenthe downwardly-directed surface of the punch support and anupwardly-directed flange surface of the sleeve.

6. In a turret punch press of the type producing a single cut for eachstroke; a punch assembly comprising; a cylindrical upper guide portionadapted to slide in the bore of the turret; a cylindrical intermediateportion of reduced outside diameter relative to that of said upperportion; a generally cubical lower punch portion, the under surface ofwhich is provided with cutting edges; a sleeve encompassing saidcylindrical intermediate portion and in sliding engagement with theouter surface thereof, said sleeve also surrounding said punch portion,the outside diameter of said sleeve being equal to that of saidcylindrical upper guide portion; an initially solid stripper platehaving an outside diameter substantially equal to that of said sleevesecured to the under side of said sleeve and adapted to be pierced bysaid punch portion to form a stripper plate closely surrounding thecutting edges of said cubical punch portion; and compression springmeans urging said sleeve and stripper plate downwardly toward the workto be punched.

7. Apparatus as claimed in claim 6 characterized in that saidcompression spring means is wrapped around the outer surface of saidcylindrical intermediate portion between said upper portion and saidsleeve.

8. Apparatus as claimed in claim 6 characterized in that the undersurface of said upper cylindrical guide portion is provided with aplurality of radially extending inde'xing grooves and in that saidintermediate portion is provided with an off-center indexing pin whichprojects upwardly from said intermediate portion and is received in oneof said indexing grooves, thereby to control the angular position ofsaid punch.

9. Apparatus as claimed in claim 6 characterized in that saidintermediate portion comprises an upper half and a lower half; furthercharacterized in that said generally cubical punch portion has arcuatecutouts in the side walls thereof forming axially extending truncatedcylindrical grooves; further characterized in that nibbling heels areprovided in said grooves, said heels having resiliently supported upperportions and truncated cylindrical lower portions fitting into thetruncated cylindrical grooves in the side walls of the punch portion,each of said heels having an axially extending slot in the outer surfaceof the cylindrical portion opposite the flat surface thereof; and resilient means extending transversely through the punch from the slot of oneheel to the slot of an opposite heel for preventing angular movement ofthe heels.

10. Apparatus as claimed in claim 9 further characterized in that theunder surface of said upper cylindrical guide portion is provided with aplurality of radially extending indexing grooves and in that saidintermediate portion is provided with an off-center indexing pin whichprojects upwardly from said intermediate portion and is received in oneof said indexing grooves, thereby to control the angular position ofsaid punch.

References Cited by the Examiner UNITED STATES PATENTS 987,144 3/1911Kuechenmeister 83-140 2,160,676 5/1939 Richard 83-140 2,227,081 12/1940Gray 83-635 2,341,976 2/1944 Constantino 83-685 2,468,998 5/1949 Parsons83-140 2,882,971 4/1959 Bennett et a1 83-140 2,997,907 8/1961Constantino 83-635 3,086,418 4/1963 Levine 83-635 3,147,657 9/1964Williamson 83-140 FOREIGN PATENTS 945,873 9/1964 Great Britain.

WILLIAM W. DYER, JR., Primary Examiner. .1, M, MEISTER, AssistantExaminer.

1. A TURRET TYPE PRESS PUNCH OR THE LIKE HAVING A PUNCH MOUNTED FORVERTICAL MOVEMENT RELATIVE TO A WORK SURFACE, A COMPRESSIVE TYPESTRIPPING UNIT MOUNTED FOR PARTIAL MOVEMENT WITH THE PUNCH COMPRISING ASLEEVE SURROUNDING THE PUNCH HAVING A DOWNWARDLY DIRECTED SURFACEADJACENT THE PUNCH CUTTING SURFACE AND HAVING MEANS FOR ATTACHING ASLEEVE TO THE PUNCH SO THAT THE SLEEVE MOVES PARTIALLY WITH THE PUNCHBUT IS FREE TO MOVE WITHIN DEFINED LIMITS IN VERTICAL DIRECTIONSRELATIVE TO THE PUNCH, COMPRESSION SPRING MEANS FOR CONTINUALLY URGINGTHE SLEEVE IN THE DIRECTION OF THE WORK SURFACE, SAID SPRING MEANS BEINGMOUNTED CONCENTRIC TO ONE PORTION OF THE PRESS AND BEARING ON ANUPWARDLY DIRECTED SURFACE OF THE SLEEVE, A STRIPPER COMPRISING A FLATMETAL DISK SUPPORTED BY THE SLEEVE ON ITS DOWNWARDLY DIRECTED SURFACE BYA PLURALITY OF MAGNETS LOCATED WITHIN THE DOWNWARDLY DIRECTED SURFACE OFTHE SLEEVE, SAID STRIPPER FORMING A SURFACE CONTIGUOUS TO AND IN THESAME PLANE AS THE PUNCH CUTTING SURFACE WHEN SAID SURFACE IS NOT INCONTACT WITH THE BLANK WHEREBY UPON POSITIONING OF THE BLANK ANDLOWERING OF THE PUNCH PROXIMATE THE BLANK THE STRIPPER CONTACTS ANDPRESSES THE BLANK AGAINST THE WORK SURFACE WHILE THE PUNCH PASSESTHROUGH THE BLANK AND AS IT IS WITHDRAWN, AN AXIAL DIRECTED SLOT FORMEDIN THE SLEEVE AND A STUB MOUNTED IN THE PUNCH AND EXTENDING THROUGH SAIDSLOT, WHEREBY MOVEMENT OF THE SLEEVE INDEPENDENT OF THE PUCH ISDETERMINED BY THE LIMITS OF THE SLOT.